Endocrine System Notes - Coral Springs Charter School

Endocrine System

Endocrine System

? Function of the Endocrine System ? to secrete hormones ? chemical messengers that coordinate and direct target cells and organs.

? ENDOCRINE GLANDS

? Secrete hormones directly into bloodstream ? Ductless

? EXOCRINE GLANDS ? secrete substances through a duct (sweat, salivary, lacrimal and pancreas)

Hormonal Control

? NEGATIVE FEEDBACK

? Drop in hormone level triggers a chain reaction to increase secretion, for example

1. Blood level of hormone falls 2. Brain gets message and sends out hormone to

stimulate gland 3. Gland stimulates more hormone 4. When blood levels of hormone increase, the brain

hormones stop

Hormonal Control

? Nervous Control ? in some cases, sympathetic nervous system causes direct release of hormone from gland (for example, when stress causes the adrenal medulla to secrete adrenalin)

PITUITARY GLAND

? Tiny structure the size of a grape

? Located at the base of the brain

? Connected to the hypothalamus

? Divided into anterior and posterior lobes

? The "Master Gland"

Anterior Pituitary Lobe

? GROWTH HORMONE - GH

(SOMATOTROPIN) responsible for growth and development

? PROLACTIN ? develops breast tissue, stimulates production of milk after childbirth

? THYROID-STIMULATING HORMONE ? TSH -

stimulates thyroxine

? ADRENOCORTICOTROPIC HORMONE ?

ACTH ? stimulates adrenal cortex

? FOLLICLE-STIMULATING HORMONE ? FSH - stimulates growth of graafian follicle and production of estrogen in females, sperm in males

? LUTEINIZING HORMONE ? LH ? stimulates ovulation and formation of corpus luteum, which produces progesterone in females

Posterior Pituitary Lobe

? VASOPRESSIN ? converts to ADH (antidiuretic hormone) in the bloodstream, acts on kidney to concentrate urine and preserve H2O in the body

? OXYTOCIN ? released during childbirth causing contractions of the uterus

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